Purified hydrogen gas is used in the manufacture of many products including metals, edible fats and oils, and semiconductors and microelectronics. Purified hydrogen gas is also an important fuel source for many energy conversion devices. For example, fuel cells use purified hydrogen gas and an oxidant to produce an electrical potential. Various processes and devices may be used to produce the hydrogen gas that is consumed by the fuel cells. One such process is steam reforming, in which a reforming catalyst is used to produce hydrogen gas from a carbon-containing feedstock and water.
Steam reforming of water and a carbon-containing feedstock to produce hydrogen gas is an endothermic reaction. Hydrogen-producing steam reforming reactions are typically performed at elevated temperatures, such as temperatures of at least 200° C., and more typically at least 350° C. The desired steam reforming temperature, or range of temperatures, will tend to vary according to a variety of factors, including the composition of the carbon-containing feedstock and the steam reforming catalyst being utilized to catalyze the hydrogen-producing steam reforming reaction. As an illustrative example, steam reforming of methanol to produce hydrogen gas is typically performed at a temperature of 350-500° C., while many hydrocarbons are reformed to produce hydrogen gas at a temperature of 700-900° C.